The invention relates to the field of signature verification on documents, and more specifically to the creation and use of digital signatures on hardcopy documents.
The processing of hardcopy documents, such as paper checks (cheques), having human handwritten signatures is a time-consuming and labor-intensive task. The accurate processing of large numbers of documents for signature verification is often required but difficult to achieve. Banks are under severe time pressure to process a massive volume of checks everyday. Moreover, the variations of a person's signature, the changes of the signature of a person due to aging and the differences of styles of signatures among people from different cultures and different parts of the world such as Chinese style, English style, etc., add complexity to the task.
Even the modern-day computerized systems with artificial intelligence/pattern recognition capabilities encounter major challenges in making a decision when verifying a human signature since many different parameters and factors are used.
A number of proposals have been set forth to substitute electronic checks for paper checks in order to escape from the time consuming and costly processing of paper checks. However, paper checks have been used for a long time, and will likely remain a preferred payment instrument for many years to come.
The inadequacy of prior-art methods and systems for handling paper checks also results in a large number of fraudulent checks being honored, causing a huge financial loss everyday.
In order to solve the problem of fraudulent checks and other documents, it is not enough to verify that a signature on a particular document is authentic. Using modern technology is becoming easier and easier to exactly copy a signature from one document to another. It is therefore helpful to produce a signature that is unique to the signor as well as to document upon which it is written. In this way, it can easily be determined when a signature that has been written for one document has been forged onto another document, even if the signature appears exactly the same as on the original document.
U.S. Pat. No. 6,081,610 to Dwork et al. (Dwork) teaches a system and method for verifying signatures on documents. Dwork generates a digital signature on a hardcopy document using a private key along with data pertaining to the document itself consisting of a scanned bitmap of the document. However, Dwork is inefficient because the signature contains an entire bitmap of the hardcopy document and thus requires a large amount of data. Moreover, Dwork is limited since all data required to be written on the check must be written before generating the digital signature. There is no provision for allowing some extra information to be added to the check between generating the digital signature and verifying the document.
Also, Dwork's signature device includes or must be attached to a bulky scanner, reducing the device's portability. The large amount of data contained in the signature requires a great deal of processing and storage within the signature device. The large amount of data contained in the signature additionally wastes bandwidth when the signature is transmitted for verification.
It is an object of the present invention to provide an apparatus and method for the generation and verification of signatures which identify the signor as well as the document with which they are associated. It is an additional object of the present invention to provide a system and method for quickly and accurately generating and verifying signatures associated with hardcopy documents using data selected from data required to be on the document. A further object of the present invention is to allow the addition of data on the document between the steps for generating the signature and the steps for verifying the signature associated with the document.